Title: Correlated interlayer exciton insulator in heterostructures of monolayer WSe₂ and moiré WS₂/WSe₂

Abstract

Moiré superlattices in van der Waals heterostructures have emerged as a powerful tool for engineering quantum phenomena. Here, in this work, we report the observation of a correlated interlayer exciton insulator in a double-layer heterostructure composed of a WSe₂ monolayer and a WS₂/WSe₂ moiré bilayer that are separated by ultrathin hexagonal boron nitride. The moiré WS₂/WSe₂ bilayer features a Mott insulator state when the density of holes is one per moiré lattice site. When electrons are added to the Mott insulator in the WS₂/WSe₂ moiré bilayer and an equal number of holes are injected into the WSe₂ monolayer, a new interlayer exciton insulator emerges with the holes in the WSe₂ monolayer and the electrons in the doped Mott insulator bound together through interlayer Coulomb interactions. The interlayer exciton insulator is stable up to a critical hole density in the WSe₂ monolayer, beyond which the interlayer exciton dissociates. Our study highlights the opportunities for realizing quantum phases in double-layer moiré systems due to the interplay between the moiré flat band and strong interlayer electron interactions.

Authors:

Zhang, Zuocheng  ^[1];

• Search DOE PAGES for author "Zhang, Zuocheng"
• Search DOE PAGES for ORCID "0000-0001-7851-6101"

Regan, Emma C.  ^[2];

• Search DOE PAGES for author "Regan, Emma C."
• Search DOE PAGES for ORCID "0000-0002-9100-6031"

Wang, Danqing ^[2]; Zhao, Wenyu ^[1]; Wang, Shaoxin ^[1]; Sayyad, Mohammed ^[3]; Yumigeta, Kentaro ^[3]; Watanabe, Kenji  ^[4];

• Search DOE PAGES for author "Watanabe, Kenji"
• Search DOE PAGES for ORCID "0000-0003-3701-8119"

Taniguchi, Takashi  ^[4];

• Search DOE PAGES for author "Taniguchi, Takashi"
• Search DOE PAGES for ORCID "0000-0002-1467-3105"

Tongay, Sefaattin  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-8294-984X"

Crommie, Michael  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-8246-3444"

Zettl, Alex  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-6330-136X"

Zaletel, Michael P. ^[2]; Wang, Feng  ^[5]

• Search DOE PAGES for author "Wang, Feng"
• Search DOE PAGES for ORCID "0000-0001-8369-6194"

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States)
2. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Materials Sciences Division
3. Arizona State Univ., Tempe, AZ (United States)
4. National Institute for Materials Science (NIMS), Tsukuba (Japan)
5. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Materials Sciences Division; Kavli Energy NanoScience Institute, Berkeley, CA (United States)

Publication Date:

Mon Aug 08 00:00:00 EDT 2022

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); US Army Research Office (ARO); USDOD; National Science Foundation (NSF)

OSTI Identifier:

1994334

Grant/Contract Number:  

AC02-05CH11231; SC0020653; W911NF-17-1-0312; CMMI-1933214; 1935994; 1904716; DMR-1552220; DMR-1955889

Resource Type:

Accepted Manuscript

Journal Name:

Nature Physics

Additional Journal Information:

Journal Volume: 18; Journal Issue: 10; Journal ID: ISSN 1745-2473

Publisher:

Nature Publishing Group (NPG)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; nanoscale devices; two-dimensional materials